It's probably the multiple decimal places that are causing the problem, perl is recognising the value as a string, and giving you a warning (quite reasonably IMHO).

your best bet is to strip the primary version number and compare that...

$sw_fields[2] =~ m/^(\d*)/; # match the primary version
if ($1 and $ver <= $1) {
    # do your stuff
[download]

(untested)

jdporter reparented from 523716